Swiss voters narrowly backed proposals to curtail immigration from the European Union in a referendum last Sunday that has already drawn criticism from the 28-member bloc.

Switzerland's business elite fears the curbs, which the Swiss government has three years to draft law for, will harm competitiveness, a view Moody's echoed on Tuesday.

"The introduction of quotas on labour immigration could reduce housing demand, thereby exerting pressure on residential house prices, and potentially leading to a faster-than-anticipated slowdown in residential housing markets," Moody's said.